I just cleaned the sending fuel guage sending unit in my 1991 300D 2.5 and I wanted to pass along that the unit is removed through the trunk, not under the back seat, for this particular model. I started by removing the rear seats and removed the plastic 6 inch body plug, but nothing was there aside from the tank itself. I removed the carpeting in the trunk and these she was. I cleaned the tube with brake cleaner to remove all that gooey black stuff, then I soaked the tube in ATF. I put it all back together and now my fuel guage does not dance around like a pin ball flipper.

Mine is going through the disco dance once I get to the 1/2 full mark, and I wondered if there was a solution other than replacement...I'll check my manual to see if I can get to mine through the trunk as well.

What car are you having trouble with? If it is the 300E, I would pull back the single piece of vertical carpeting to see if you can see the sending unit. Mine was dead center on the top of the seat back, looking from inside the trunk. You can even feel it through the carpeting.

Liquid gasoline does not readily explode. It must first be vaporized and mixed with sufficient amounts of oxygen.

However it will burn proportional to the amount of oxygen reaching the flame.

Not saying that it is not dangerous... only that danger and caution should be in proper perspective.

You can throw a burning cigarette into a bucket of gasoline and the liquid gasoline will extinguish the burning ash... the same as water would.

Don't suggest you try it... just take my word for it. An open flame however will set the gasoline in the bucket afire.... but it will not explode because oxygen can only reach the limited surface of the liguid.

Caution is key, just ask XXXXXXX, in Baltimore MD how a few Porsches took an unexpected flight through the roof of the service building and landed on the main road, 3 weeks ago, becuase of a static electricity spark set off some gasoline. I won't say the name of the dealership, but those who live in Baltimore know that they have a huge empty lot where Porsche's used to sit, but the MBZ, VW, Subaru and Audi building are ok.

I'm no great mechanic, but from the straightforward instructions I found in this and related postings on fuel senders, I was able to correctly diagnose and repair my car. I figure it saved me a few hundred bucks; but more importantly, I feel GREAT that I pulled it off (without blowing up the house!!!)

In my case, the problem was varnish deposits and a broken copper wire (the one that carries the "empty" signal to the indicator light on the dash). By CAREFULLY cleaning the device as instructed and then resoldering the broken copper wire back in place, the problems were eliminated.) I got everything back in place with the proper torque, and voila...

This archive is a tremendous resource to Benz owners. Thanks to all of you who share your knowledge and experience so generously. It's really appreciated by those of us that love these cars but lack the same level of expertise!!!